Compound die for punching two concentrically shaped sheet circular members from strap material in punch presses with vertical disposition of blanking planes

ABSTRACT

A compound die is disclosed for punching concentrically shaped circular sheet members from a strap material in punch presses with a vertical disposition of the blanking planes. The die is provided with a lifter for removing the circular members whose surface, directly contacting the latter, is inclined, while the lifter of the strap is provided with guide chutes having springloaded clamps for pressing the strap against the face of the female die as well as for pressing the same against one of the chutes. In addition, the female die, the lifter for removing the circular member, the lifter for removing the central portion, which is a blank of a second member, and the internal punching ring are provided with means for separation of the circular member and its central portion from the surfaces of the punches, female die and the lifters as well as for keeping the central portion in place for a time during the opening of the die.

United States Patent Inventors 36, all of Baku, U.S.S.R. Appl. No. 872,528 Filed Oct. 30, 1969 Patented Oct. 12, 1971 COMPOUND DIE FOR PUNCHING TWO CONCENTRICALLY SHAPED SHEET CIRCULAR MEMBERS FROM STRAP MATERIAL IN PUNCH PRESSES WITH VERTICAL DISPOSITION OF BLANKING PLANES 2 Claims, 6 Drawing Figs.

US. Cl 83/132, 83/133, 83/140, 83/446, 83/449, 83/459, 83/621 Int. Cl B26t 1/44, B26f l/l4 Field of Search 83/132,

Primary Examiner-James M. Meisler AttarneyWaters, Roditi, Schwartz & Nissen ABSTRACT: A compound die is disclosed for punching concentrically shaped circular sheet members from a strap material in punch presses with a vertical disposition of the blanking planes. The die is provided with a lifter for removing the circular members whose surface, directly contacting the latter, is inclined, while the lifter of the strap is provided with guide chutes having spring-loaded clamps for pressing the strap against the face of the female die as well as for pressing the same against one of the chutes. In addition, the female die, the lifter for removing the circular member, the lifter for removing the central portion, which is a blank of a second member, and the internal punching ring are provided with means for separation of the circular member and its central portion from the surfaces of the punches, female die and the lifters as well as for keeping the central portion in place for a time during the opening of the die.

PATENTEDUCTIZIHYI 3 61] 854 sum 3 0F 3 2. /9 r E! v 25 FIG. 6

COMPOUND DIE FOR PUNCHING TWO CONCENTRICALLY SHAPED SHEET CIRCULAR MEMBERS FROM STRAP MATERIAL IN PUNCH PRESSES WITH VERTICAL DISPOSITION OF BLANKING PLANES The present invention relates to punch presses with a vertical disposition of blanking planes employed for punching two concentrically shaped sheetcircular members. More specifically, this invention relates to compound dies used in such presses. The proposed dies can be used for simultaneous punching of stator laminations and blanks of rotor laminations of magnetic circuits of electric machines, for example induction motors, from a strap or a band.

Known in the art is an automatic punch press with vertically disposed blanking planes employed for punching stator and rotor laminations of electric machines.

This punch press is provided with at least two dies arranged one above the other so that their blanking planes are located in one vertical plane. A circular member, e.g. a stator lamination, and a central portion, i.e. the blank of the second member, are punched from a strap which is then moved downwards, into the second die in which another member, e.g. a rotor lamination, is punched from the blanked strap.

In this press, the upper die for simultaneously punching a circular member and a blank of a second member is made in the form of a conventional compound die comprising a stationary plate carrying a spring-loaded female die and a strap lifter and a movable plate provided with punches, punching rings internal and external for punching the circular member and its central portion, which is a blank of the second member, and lifters for removing the circular member and its central portion.

However, this die is primarily used for punching members in a horizontal or slightly inclined position of the blanking planes.

Such a construction of the known dies with vertically disposed blanking planes does not provide for an oriented motion of the strap within the die as well as for a pressing of the strap against the face of the female die, and for efficient separation of the punched circular member from its central portion, which is a blank for the second member, and removal of these members from the blanking zone in two flows effected by gravity.

An object of the present invention is to provide a compound die for punch presses with a vertical disposition of the blank ing planes which will provide for a strictly oriented travel of the strap material and reliable positioning of this material on the face of the female die.

Another object of the invention is to provide an efficient separation of the blanked circular member from its central position.

Still another object of the invention is to provide gradual and smooth withdrawal of the circular member from the punches during the opening of the dies and removal of the ready member and its central portion in two independent flows efi'ected by gravity.

These objects are attained by providing a compound die for a punch press with a vertical disposition of the blanking planes comprising a stationary plate carrying a spring-loaded female die and a strap lifter, and a movable plate provided with punches, punching rings for punching a circular member and its central portion, which is a blank for a second member, and lifters for removing the circular member and its central portion; according to the invention, the surface of the lifter of the circular member which is in direct contact therewith is inclined so that its lower point is more distant from the surface of the movable plate than the upper point while the strap lifter is provided with guide chutes located in the lower and upper portions thereof and having clamps for pressing the strap against the face of the female die, another clamp being arranged in the upper chute for pressing the strap against the lower chute. In further accordance with the invention, the female die, the litter of the circular member, the lifter of the central portion and the internal punching ring are provided with means for separation of the circular member and its central portion from the surfaces of the punchers, female die and lifters and for holding the central portion for a time during the opening of the die.

it is expedient that the inclination of the surface of the circular member is within 30 to 40 minutes.

Such a construction makes it possible to provide an oriented feed of the strap to the blanking zone of the upper die of the punch press with a vertical disposition of the blanking planes and to separate the circular member and its central portion, which is a blank for the second member punched in the upper die and falling by gravity, into two independent flows. In thiscase the circular member is displaced beyondthe punching press while the blank of the second member is transferred into the lower die.

Such an operation is possible due to the fact that the guide chutes provide for a strict orientation of the strap fed into the blanking zone with respect to disposition female die while the clamps located in the upper chute provide for pressing the strap against the face of the female die. The surface of the lifter of the circular member directly contacting the latter is slightly tilted and this makes it possible to smoothly remove the circular member with the punch and to provide for a properly oriented fall of this member into an attachment for removal from the die area. Furthermore, the provision of the female die, the lifter of the circular member, the lifter of the central portion and the internal punching ring with means separating the circular member and its central portion from the blanking surfaces of the punches, female die and lifter make it possible to provide an efficient separation of the circular member from its central portion after effecting the punching operation in the die and holding of the central portion within the blanking zone for a time during the opening of the die. The latter allows the punched central portions to be held in a strictly vertical position before the fall and provides for a strict orientation of these portions during their further travel to the blanking zone of the lower die where the second member is punched.

Other objects and advantages of the present invention will be apparent from consideration of the following description of a particular embodiment thereof in the form of a die for punching stator laminations and blanks of rotor laminations of induction motors from a metal strap, reference being made to the accompanying drawings, in which:

FIG. 1 is a sectional view of the die according to the invention;

FIG. 2 is a sectional view taken along line [1-1] in FIG. 1 showing the stationary plate of the dies;

FIG. 3 is a plan view of the strap lifter of the die;

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3; and

FIG. 5 is a sectional view taken along line VV in FIG. 3; FIG. 6 is a sectional view taken along lines VIVI of FIG. 1 showing the movable plate of the die.

The proposed compound die comprises a stationary plate 1 /FIG. 1/ and a movable plate 2 interconnected by columns 3. One end of each column 3 is rigidly secured in the stationary plate 1 while the other end is mounted in ball bearings 4 of a bushing 5 rigidly secured to the movable plate 2.

The stationary plate I carries a springloaded female die 6 and a strap lifter 7.

The female die consists of a central portion 8, a ring 9 and sectors 10 disposed about the ring 9. The.central portion 8 is pressed into the female dieholder II and serves for punching a central aperture in the blank of the rotor lamination while the sectors are rigidly connected to the female dieholder II by means of screws 12, the sectors 10 having a shape, as shown in FIG. 2 for punching the slots in the process of making a stator lamination of an induction motor.

The ring 9 provides for punching a blank of a rotor lamination and is associated with pushers 13 (FIG. I) located in slots of the stationary plate I and female dieholder II and bearing upon a ring 14 associated with a bumper device (not shown) of the punch press.

Provided between the female die holder 11 and the ring 9 is a free space 15 for the possibility of moving the ring 9 during the punching of the members in the die. The space 15 is protected from plugging with rejects during the punching operation by a spring-loaded protecting ring 16.

The strap lifter 7 is located in the blanking plane and consists of a flat member with a round hole 17 (FIG. 3) in the central portion corresponding to the size of the female die 6. Mounted on the lifter 7 in the upper and lower portions thereof are guide chutes l8 and 19 respectively, each being provided with a spring-loaded clamp 20 for pressing the strap against the face 6 of the female die, the upper chute being also equipped with a clamp 21 consisting of a flat spring pressing the strap against the lower chute 18, thus strictly orienting the strap within the blanking zone.

Each spring-loaded clamp 20 consists of a rigid bent spring 22, one end of which is connected to the chute and the other end is pressed against the lifter 7 by an additional spring 23.

The chutes 18 and 19 have chambers 24 at the entry side of the strap, said chambers serving for additional orientation of the strap when introducing it into the blanking zone under the clamps 20.

Provided in the upper part of the lifter 7 is a guide plate 25 (FIG. 2) located near the lifter 7 with a small gap therebetween and preventing the strap from bending during the travel of the strap within the blanking zone.

The movable plate 2 (FIG. 1) has a punch holder 26 with punches 27 secured therein and adapted for punching the slots in the stator laminations, a punch 28 for punching a central aperture in the rotor blank, an external punching ring 29 for punching out the external contour of the stator lamination and an internal punching ring 30 for separating the central portion of the stator lamination, which is a blank of the rotor lamination, from the stator lamination.

The punch 28 is located in the center of the punch 26 as shown in FIG. l, and the punches 27 are located along a circle about the internal punching ring 30 which is in turn located concentrically with respect with the punch 28.

The punches 27 have passages for air supply to prevent adhesion of the rejects of the punched members to the end face of the punches 27.

Located on the movable plate 2 are a lifter 32 for removing the stator lamination from the punches 27 and a lifter 33 for removing the blank of the rotor lamination from the punches 28. The lifters 32 and 33 are capable of moving relative to the punches 27 and 28, for which purpose the lifter 32 is provided with openings 34 (FIG. 1) and the lifter 33 is provided with an opening 35.

The surface 36 of the lifter 32 directly contacting the blanked stator lamination is inclined so that its lower point C is more distant from the surface of the movable plate 2 than the upper point D, the angle of this inclination being within the range of 30 to 40 minutes, i.e. the above-said difference in the points mentioned is 3 to 4 mm. over a diameter of the blanked stator about 350 mm. This is necessary for smooth and uniform removal of the blanked stator lamination from the punches 27.

Each opening 34 in the lifter 32 is provided with a plastic insert 37 reducing the friction between the movable parts, while ensuring an additional support for the punches 27 and increasing the accuracy of the punched slots.

The lifter 32 is connected with pushers 38 resting on a ring 39 and associated with a mechanism not shown of the punch press synchronizing the removal of the ready stator laminations with the movement of the sliders.

The lifter 33 is located by a spring 40.

The ring 9 of the female die 6, the lifter 32 for removing the stator lamination, the lifter 33 for removing the rotor lamination and the internal punching ring 30 are provided with means in the form of spring-loaded pushers 41 for separation of the stator lamination and the blank of the rotor lamination from the blanking faces and for holding it for a time during the opening of the die.

The proposed die operates as follows:

0n introducing the strap into the guide chutes 18 and 19 in the direction indicated by the arrow E, the spring 21 presses the strap against the lower chute 13 while the springs 22 and 23 and the guide plate 25 press the strap against the face of the female die (FIG. 1). When the movable plate 2 approaches the stationary plate 1, the columns 3 move in the ball bearings 4 of the bushing 5, and the lifters 32 and 33 press the strap against the female die 6.

When the plates 1 and 2 approach each other, the punches 27 enter the sectors 10 punching slots in the strap for the next stator lamination, the external punching ring 29 interacting with the peripheral portions of the sectors 10 to punch out the outer contour of the stator lamination, the punch 28 entering the openings 42 of the central portion 8 of the female die and punching out a central opening in the strap for the next blank of the rotor lamination.

During the complete closing of the plates 1 and 2, the internal punching ring 30, by interacting with the inner contour of the sectors 10, punches out the contour of the blank of the rotor lamination. The rejects produced during the punching of the slots and central opening fall down through the openings 43 provided in the stationary plate 1 and in the female dieholder 11.

in the process of punching, during the closing of the plates 1 and 2 and during the interaction of the punches and punching rings with the strap and female die, the lifters 32 and 33 move relative to the punches 27 and 28 and relative to the punching rings 29 and 30, thus approaching the punchholder 26. At the same time the lifter 7 moves relative to the female die 6 approaching the female dieholder ll.

When the movable plate 2 moves away from the stationary plate 1, the lifter 33 returns, under the action of the springs 40, to the initial position and removes the blank of the rotor lamination from the punch 28. The ready stator lamination remains on the punches 27. The pushers 41 of the lifter 33 and the pushers 13 of the ring 9 separate the blank of the rotor lamination from the above-said members and for a time hold this blank in a strictly vertical position, whereafter during further movement of the plate 2 from the plate 1, the pushers open, thus releasing the blank which falls down keeping the prescribed vertical position.

At the same time, the strap lifter 7 returns to the vertical position under the action of the springs 44 and removes the remnant of the strap from the female die 6.

When the plates 1 and 2 open almost completely, the synchronizing mechanism of the punch press acts through the ring 39 and pushers 38, upon the lifter 32 returning it to the initial position. On returning to the initial position, the lifters 32 remove the ready stator lamination from the punches 27. Due to the fact, that the surface of the lifter 32 is tilted, the removal of the stator lamination from the punches 27 is first effected in the lower portion, then on the sides and thereafter in the upper portion, thus providing for smooth and gradual removal of the stator lamination preventing it from performing an unexpected jump from the punches. The pushers of the lifters 32 separate the stator lamination from the lifter surface, and the stator lamination slides down from the lifter 32 onto a chute (not shown) guiding the completed member to the assembly line.

The lifter 33 is provided with a chamber 45 which prevents the stator lamination from jumping off in case of a probable blow of this lamination about the lifter 33 during the fall.

We claim:

l. A compound die for punching two concentrically shaped circular sheet members from strap material in punch presses with a vertical disposition of the blanking planes comprising in combination: a stationary plate; a movable plate connected to said stationary plate; a spring-loaded female die located on said stationary plate; a lifter of the strap material located on said stationary plate; punches located on said movable plate; punching rings for punching a circular member and its central portion which is a blank for a second member, said rings being disposed on said movable plate; a further lifter for removing chute; and means for separating said circular member and its central portion from the surfaces of the punches, female die and lifters and for keeping the central portion in place for a time during the opening of the die, said means being located in said female die, said further lifter of the circular member, and in said internal punching ring.

2. A compound die as claimed in claim 1, in which the surface of the lifter is inclined at an angle of 30 to 40 minutes. 

1. A compound die for punching two concentrically shaped circular sheet members from strap material in punch presses with a vertical disposition of the blanking planes comprising in combination: a stationary plate; a movable plate connected to said stationary plate; a spring-loaded female die located on said stationary plate; a lifter of the strap material located on said stationary plate; punches located on said movable plate; punching rings for punching a circular member and its central portion which is a blank for a second member, said rings being disposed on said movable plate; a further lifter for removing the circular member located on said movable plate and having an inclined surface with a lower point thereof somewhat more distant from the surface of said movable plate than an upper point; a third lifter for removing said central portion located on said movable plate; guide chutes arranged in the lower and upper portions of said lifter of the strap material; clamps for pressing the strap material against the face of said female die and positioned in said chutes; another clamp for pressing the strap material against the lower chute positioned in said upper chute; and means for separating said circular member and its central portion from the surfaces of the punches, female die and lifters and for keeping the central portion in place for a time during the opening of the die, said means being located in said female die, said further lifter of the circular member, and in said internal punching ring.
 2. A compound die as claimed in claim 1, in which the surface of the lifter is inclined at an angle of 30 to 40 minutes. 